Liability for Mortage Loan Repurchase Losses (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Liability For Mortgage Loan Repurchase Losses [Abstract]
Balance, beginning of period	$ 1,207	$ 1,263	$ 1,289	$ 1,033
Loan sales	20	36	55	80
Change in estimate - primarily due to credit	222	346	436	704
Total additions	242	382	491	784
Losses	(261)	(270)	(592)	(442)
Balance, end of period	$ 1,188	$ 1,375	$ 1,188	$ 1,375